With a wide range of potential applications, machine type communication (MTC) or machine to machine (M2M) communication is gaining a tremendous interest among mobile network operators, equipment vendors, MTC specialist companies, and research bodies. The idea of M2M communications is to enable M2M components to be interconnected, networked, and controlled remotely with low-cost scalable and reliable technologies. M2M communication could be carried over mobile networks (e.g. GSM-GPRS, CDMA EVDO networks). In the M2M communication, the role of mobile network is largely confined to serve as a transport network.
M2M devices or user equipment (UEs) coupled to a mobile network may be capable of replying to requests for data contained within these types of UEs. These UEs may also be capable of transmitting data autonomously and parameters defining what or when data is transmitted may be adjusted or updated responsive to trigger messages. In some instances a physical hybrid automatic request (HARQ) indicator channel (PHICH) may be used (e.g., by a base station) to send acknowledgments (ACKs) or negative acknowledgement (NAKs) to these UEs responsive to successfully or unsuccessfully receiving transmitted data via an established physical uplink shared channel (PUSCH).